From: Michaël Cadilhac <michael@cadilhac.name>
Date: Mon, 22 Feb 2010 08:59:26 +0000 (+0100)
Subject: usb_stream: Check for NULL-ness before dereferencing
X-Git-Tag: v1.0.23~2
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=e3b3c401bb9f6ff4d428600350a53c952ad1747e;p=alsa-plugins.git

usb_stream: Check for NULL-ness before dereferencing

 * usb_stream/pcm_usb_stream.c (snd_pcm_us_stop): Prevent
   dereferencing when structure is not initialized.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

diff --git a/usb_stream/pcm_usb_stream.c b/usb_stream/pcm_usb_stream.c
index 4097693..cd761fb 100644
--- a/usb_stream/pcm_usb_stream.c
+++ b/usb_stream/pcm_usb_stream.c
@@ -1,7 +1,7 @@
 /*
  *  PCM - USB_STREAM plugin
  *
- *  Copyright (c) 2008 by Karsten Wiese <fzu@wemgehoertderstaat.de>
+ *  Copyright (c) 2008, 2010 by Karsten Wiese <fzu@wemgehoertderstaat.de>
  *
  * This library is free software; you can redistribute it and/or modify
  * it under the terms of the GNU Lesser General Public License as
@@ -256,8 +256,11 @@ static int snd_pcm_us_start(snd_pcm_ioplug_t *io)
 static int snd_pcm_us_stop(snd_pcm_ioplug_t *io)
 {
 	snd_pcm_us_t *us = io->private_data;
-	VDBG("%u", us->uus->s->periods_done);
 
+	if (!us->uus->s)
+	  return 0;
+
+	VDBG("%u", us->uus->s->periods_done);
 	if (io->stream == SND_PCM_STREAM_PLAYBACK)
 		memset(us->uus->write_area, 0, us->uus->s->write_size);